A polishing apparatus represented by a chemical mechanical polishing (CMP) apparatus polishes a surface of a target substrate by moving a polishing pad and the target substrate relatively, in a state in which the polishing pad and the surface of the target substrate are made to contact each other. The polishing pad is gradually worn by polishing of the target substrate or minute unevenness of the surface of the polishing pad is collapsed, which results in decreasing a polishing rate. For this reason, dressing is performed on the surface of the polishing pad by a dresser with multiple diamond particles electrodeposited on a surface thereof or a dresser with brush implanted into a surface thereof to form the minute evenness is formed again on the surface of the polishing pad (for example, refer to JP 2014-42968 A and JP 2010-76049 A).
The dresser is pressed on the polishing pad, swings on the polishing pad while rotating, and cuts the surface of the polishing pad. To maintain polishing performance (particularly, uniformity of polishing or a predetermined polishing profile) for the target substrate, force cutting the surface of the polishing pad is preferably constant regardless of a position on the polishing pad. For this reason, it is general to control force of the dresser pressing the polishing pad constantly.
However, even though the force of the dresser cutting the polishing pad is constant, force of the dresser polishing the polishing pad is not always constant.
The present embodiment has been made in view of the above problem and an object of the present embodiment is to provide a polishing apparatus including a dresser capable of cutting a polishing pad with approximately constant force and a control method thereof.